Matic joined United from champions Chelsea last month.
He headed north in a £40m deal.
Many were surprised that the Blues sold a key player to a title rival.
And when quizzed about the transfer, Conte said: "You must ask the club about this."
Tiemoue Bakayoko was snapped up from Monaco earlier in the summer and is likely to take Matic's place in the team.
The Frenchman won't play on Sunday though, when Chelsea take on Arsenal in the Community Shield.
Bakayoko had a knee operation earlier this summer and isn't yet fully fit.
Despite being without his new man, Conte is keen to make a statement at Wembley.
"We want to try to start the season with a win," he said. "I hope to see a good game from the players and for the people.
"This is the first trophy of the season. It's an important game. We want to play a good game with good intensity."
On Chelsea's injuries going into the new season, Conte added: "Only two players, Eden Hazard and Bakayoko [aren’t available].
"They are working to be available soon. For the first PL match? No. There are recovering very well but they are not still ready to start the season.
"You know very well about Eden, an ankle problem, after a surgery it is right to respect the time needed."
